CIRCUIT ELECTRONIQUE D'INJECTION DE SONNERIE

摘要

This circuit concerns a development and improvement of the circuit disclosed in French patent application No. 7629418. It is essentially improved in that no auxiliary triacs are provided in the control circuit (C) in addition to the two triacs (1, 1') present in the circuit. Moreover, the present control circuit essentially has only one pair of complementary transistors (2, 2') and supplies the gates of the triacs with a direct current which is always higher than the trigger current of the triacs. This gate current is produced by the AC ringing voltage. <IMAGE>